DATAMONGO-2599 - Eagerly consider enum types as simple types.

MongoSimpleTypes now eagerly checks if a type is a simple one to avoid PersistentEntity registration for ChronoUnit.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/MongoSimpleTypes.java

@@ -48,6 +48,7 @@ import com.mongodb.client.model.geojson.Polygon;
  *
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public abstract class MongoSimpleTypes {
 
@@ -109,6 +110,10 @@ public abstract class MongoSimpleTypes {
 		@Override
 		public boolean isSimpleType(Class<?> type) {
 
+			if (type.isEnum()) {
+				return true;
+			}
+
 			if (type.getName().startsWith("java.time")) {
 				return false;
 			}

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/mapping/MongoMappingContextUnitTests.java

@@ -17,6 +17,7 @@ package org.springframework.data.mongodb.core.mapping;
 
 import static org.assertj.core.api.Assertions.*;
 
+import java.time.temporal.ChronoUnit;
 import java.util.AbstractMap;
 import java.util.Collections;
 import java.util.Locale;
@@ -160,6 +161,18 @@ public class MongoMappingContextUnitTests {
 				.withMessageContaining("score").withMessageContaining("Float").withMessageContaining("Double");
 	}
 
+	@Test // DATAMONGO-2599
+	void shouldNotCreateEntityForEnum() {
+
+		MongoMappingContext context = new MongoMappingContext();
+
+		BasicMongoPersistentEntity<?> entity = context.getRequiredPersistentEntity(ClassWithChronoUnit.class);
+
+		assertThat(entity.getPersistentProperty("unit").isEntity()).isFalse();
+		assertThat(context.hasPersistentEntityFor(ChronoUnit.class)).isFalse();
+		assertThat(context.getPersistentEntity(ChronoUnit.class)).isNull();
+	}
+
 	public class SampleClass {
 
 		Map<String, SampleClass> children;
@@ -226,4 +239,9 @@ public class MongoMappingContextUnitTests {
 
 		@TextScore Locale score;
 	}
+
+	class ClassWithChronoUnit {
+
+		ChronoUnit unit;
+	}
 }